Function for splitting conduit by sequence and not element

[Termina1]

Hi,
there is a function called splitOnUnboundedE, which splits conduit by some element of sequence, that this conduit contains.
Is there any way to split not by an element, but using a sequence? I stumbled upon it trying to do something similar to linesUnbounded, but I need so split file using sequence of double newline symbols.

Is it possible now with any existing combinator or if not, would such a function be useful for others to be in combinators library?

In case it is, I tried to modify splitOnUnboundedE, there are some inefficiencies, but is the idea may be useful?

splitOnSeq :: (Monad m, Seq.IsSequence seq, Eq (Element seq)) => seq -> ConduitT seq seq m ()
splitOnSeq f =
    start
  where
    start = await >>= maybe (return ()) (loop id)

    loop bldr t =
        if onull y
            then do
                mt <- await
                case mt of
                    Nothing -> let finalChunk = mconcat $ bldr [t]
                               in  unless (onull finalChunk) $ yield finalChunk
                    Just t' -> loop (bldr . (t:)) t'
            else yield (mconcat $ bldr [x]) >> loop id y
      where
        (x, y) = let (x : z) = Seq.splitSeq f t in
          (x, mconcat $ intersperse f z)

[snoyberg]

I don't think it's possible. Generally this is a non-trivial problem to solve. Not impossible or crazy, just that doing this with good performance requires some thinking. I had to do something like that for multipart form data processing in wai-extra IIRC.

Overall, I'd be in favor of some kind of an addition that does this efficiently.